Process of making chlorhydrins



May 29, 1923. 1,456,916

` G. O. CURME, JR.; ET AL PROCESS oF MAKING GHLORHYDRINS Filed 4May .121922 HX l i atented ay 29, 1923.

GEORGE o. comme, Jn., or OLENDENIN, wnsr VIRGINIA, AND CHARLES o. YOUNG,or i' ELIHIUBST, NEW YORK, ASSIGNORS TO ARBIDE AND CARBON CHEMICALS COB-POBATION, A CORPORATION OF NEW YORK. Y

PROCESS F MAKING CHLOBHYDBINS.

Application led May 12, V1922. Serial Eo. 569,391Ql To allwhomz't mayconcern.'

Be it known that we, GEORGE 0. Comin, J r., and CHARLES O. YOUNG,citizens of the United States, residing at Clendenin and 3 Elmhurst, inthe counties of Kanawha and Queens and States of West Virginia and NewAYork, respectively. have invented certain new and useful Improvements ina Process'of Making Chlorhydrins, of which the following is aspecification.

This invention relates to the manufacture of chlorhydrins ofhydrocarbons having an olene linkage, the object of the invention beingthe provision ofa simple process for the manufacture of theseproductswith high operating eiiiciency and with a minimum production 'ofobjectionable by-products. The process willbe described with specificreference to4 the prepa-ration of ethylenechlorhydrin, it beingunderstood however that the procedure is applicable directly to thepreparation of At-he corresponding compounds o other olenes, whethergaseous at usual temperatures or .-not. The termo olefine is used hereinto designate compounds having an oleine linkage, for example, the simpleoleines of the ethylene series, the dioleines, and the varioussubstituted Olefines. S0 details of procedure as hereinafter set forth,but the-procedure described is that which has been found' in ractice toa'ord. the maximum yields and 1n general the optimum results. s i

The process depends upon the well known fact that the chlorhydrins maybe prepared by the direct union of olenes with hypo- I chlorous acid inaccordance with the equa- Y tion:

For a full understanding of the present in-V tion into e ect. v

For the preparation of the sodium hypo- L chlorite solution for use inthis process,`a'

50 solution of iron-free caustic' SOdais treated with ous chlorin, withcooling to about The invention is-not restricted to the and other un 10-v until it has been convertedto an chlorite and sodium chlorid inaccordance with the equation This solution of sodium hypochlorite orliquid bleach diilers from the commercial article only in being entirelyiron-free and'iny containing but a very small proportion of free alkali,and, if properly cooled, practically no chlorate. It is preferablyprepared pared'by any other standard method, since the method of itspreparation is not an essential part of the chlorhydrin process.

In connection with the following description, itis to be understood thatthe apparatus Y equimolecular solution of sodium hypo- Y Ain aconcentration of 5% to 7% NaOCl, depending' upon the concentration ofchlor-v should be throughout constructed of acid-V v proof stoneware, orother appropriate matevrials having no injurious action upon thematerials treated. t

The hypochlorite solution contained in a storage reservoir l ispermitted to How through pipe 2 into a cell 3, hereinafter reerre to asthe first decomposing cell. This 0-1() C. b immersion in a brine tank16.

=Into this ce -there is passed through inlet pipe 4 a finely dividedstream of chlorin gas, -in quantity suiiicent to react with most but.not -quite all .ofthe sodium hy ochlorite present. The excess'ofhypochlorite, which A'may b'e in the neighborhood of O.5-`1.0%, 'is anactive factor in eliminating any free chlorin which might tend to passover with the solution into the reaction vessel beyond, and there to(give rise to ethylene dichlorid sirable by-products.

The reaction occurr' Vvolves. the setting free o hypochlorous lacid andmay-.be expressed by' t e equation:-

inthe cell 3 in l f 70 sodium4 hypochlorite 'solution may be pretioncontaining free hypochlorous acid passes through a cooling coil ofchemical stoneware, which as illustrated is also immersed in the coolingtank 6. This coil insures thorough cooling of the solution, and

also aiords time for the reactionas expressed above lto proceed tocompletion, so-

u that no chlorin passes with the solution into cated in the lower thereaction tower.

The hypochlorous acid solution then Hows directly through pipe 7 intothe lower portion of the main reaction tower 8, which isals'cons'tructed of chemical stoneware. In this tower thehypochlorousacid collects and is maintained at a constant depth ofseveral feet, overiowing into 'an auxiliary de, ,composing cell 9 asfast as it enters, after this depth has once been reached. A rapidstream of pure ethylene in finely distributed condition 1s passed intothe'reaction tower 8, preferably through a porous plate 10 loportion ofthe tower. -Under these conditions the ethylene reacts rapidly with thefree hypochlorous acid,

with the we circulated through the tower until it is consumed, a freshsupply of ethylene being added as required in order to eep the reactiontower filled with pure ethylene at substantially atmospheric pressure.-The reac` tion tower 8 is preferably. equipped with a cooling coil 11,in order that. the solution may at all times be maintainedat a' lowtem'- perature, say 0-10 C.

The solution as it leaves the reaction tower 8 consists chieHy o fethylene chlorhydr-in, together with al small amount of residual freehypochlorous acid and some residual` sodium hypochlorite.

It also contains the sodiumchlorid resulting from the previousreactions. This solution then Hows into the auxiliary decomposingcell 9,which is also cooled to 010' C'., and in which there isaddedl suHicientadditional chlorin to transform-all of the residual sodium hypochloriteinto free hypochlorous acid, and to leave the' solution falntly acidwith hydrochloric acid.

.The solution overflowing from the auxiliary decomposing cellL9 passesthrou h a cooling coil 12 to permit completion o the reactions; and thenpasses through conduit 13 into a second reaction tower 14,' which is'similar in construction t6 the tower 8, and is also preferably cooled to0-10 C. Here 65 again the solution is treated with pure ethylenesupplied from the compressor 20 and mesme excess of the requirements ofthe hypo- ,f

chlorous acid, and the uncombined excess Hows through exit pipe 21 tothe ethylene gas holder 19, and thence returns to the ethylenecirculating system. The solution inthe tower 14 is also permitted tocollect to a considerable depth, overHowing through pipe '15 into areservoir 16 from which it may be withdrawn through conduit 17 to theVstill to be-further concentrated. Inasmuch as the larger part of the'hochlorous acid is consumed in the first reaction tower 8, the tower 14may be of relatively small dimensions. It will be understood that otherunits similar to those described above may bev provided if desired inorder to bring the several reactionsv to substantial completion.

The solution contained in the reservoir 16, in addition to chlorhydrin,contains sodium chlorid, a trace of hydrochloric acid, and minute tracesof oxidizing substances such as chlorates, hypochlorites, etc. In orderto remove these traces of oxidizing substances it has been foundpreferable to treat the solution, before passing tothe still, with avery slight excess of sodium bsuliite solution, and then to fullyneutralize the free acid by calcium carbonate.

It is sometimes lfound desirable, in'order to diminish the concentrationof hypochlorous acid in the decomposing cell 3, to dilute the sodiumhypochlorite solution passing into this cell by an aqueous solution freeor substantially free from hypochlorite. This solution tends to increasethe stability of the hypochlorous solution during the period previous toits entry into the-reaction tower `8. Water may of course'be emgloyed asthe diluting medium, but it has een found advanta eous to use for thispurpose a portionv o the chlorhydrin solution already formed. Forexample, a.. art of this solution may bewithdrawn rom the reservoir 16by means of a pump. 23

(and discharged by. .conduit 22, togetherwith the sodiumlhypochlorite.solution from the'reservoir 1, into the decomposing cell 3. Thisprocedure presents the advantage that, inasmuch as thedilution is being4accomplished by a chlorhydrin solution of de. sirablel strength forsubsequent concentration, there is no'reduction of the chlorhydrincontent of the final solution such as would be the case if water wasused as the Adilutlng medium, but on the contary an augmentation of thechlorhydrin concentration.

By the process as described above it has aol imi

been found possible to prepare directly chlorhydrin solutions of anydesired strength up to -20% chlorhydrin. Such solutions are far moreconcentrated than can be prepared by known processes. Furthermore, theoperation `proceeds smoothly andwith high yields. The concentration ofthe solution to any desired higher strength, as well as the removal ofthe salt present, is easily effected by ordinary distillation processes,as well understood by those skilled in this art.A

We claim n 1. Process of making chlorhydrins from o1eines,' comprisingreacting with the hydrocarbon upon a solution containing freehypochlorous acid and a. hypochlorite, thereby preparing chlorhydrinsubstantially free from ethylene or propylene chlorids; setting freehypochlorous acid from the re-- Sidual hypochlorite; and reactin thereonwith a further quantity of the hy rocarbon. -2. In a process of makingchlorhydrins from olefines, the step which consists in bringing thehydrocarbon into reactive contact with a solution containing freehypochlorous acid and a. hypochlorite.

3. In a process of making chlorhydrins from olefines, the step whichconsists in bringing the hydrocarbon into reactive contact with asolution containing free hypo-- chlorous acid and a lhypochlorite whilefrom olefines, the steps which consist in bringing the hydrocarbon intoreactive contact with a solution containing free hypochlorous acid andhypochlorite; withdraw-v ing the solution containing the residualhypochlorite from contact with the hydrocarbon, and setting freehypochlorous acid therein; and reacting thereonwith a further quantityof the hydrocarbon.

6. In a process of making chlorhydrins from olefines, the step whichconsists in diluting a h pochlorite solution with a solution contalningchlorhydrin; setting free hypochlorous acid in the resulting mixedsolution; and reacting thereon lwith the hydrocarbon to increase thechlorhydrin concentration.

In testimony whereof, we a'lx our signatures. i

GEORGE QCURME, JIL. CHARLES o. YOUNG.

